1. Field of the Invention
This invention relates in general to stairways and in particular to storage type platforms and stairways for recreational type vehicles.
2. Description of the Prior Art
The desirability of having stairways for recreational vehicles which may be folded and stored against the wall of the vehicle has long been recognized. Such stairways should fold easily, store compactly, and have a design to insure the safety of the user.
Typical of such stairways in the current art is the device of C. D. Graves, U.S. Pat. No. 3,997,211 which includes a stairway and platform which is attachable to the wall of a recreational vehicle and which may be slid laterally from the doorway and folded for storage. The Graves device utilized parallel bar linkages for the steps; the top bars of which obstruct both sides of the steps at foot level resulting in a potentially dangerous obstacle which one may readily trip over if one should decide to laterally dismount the steps, even at ground level. The Graves device utilizes a pair of slotted guides to permit collapsing of the linkage, thus destroying the integrity of the system, particularly on uneven ground support; does not fold compactly against the vehicle, in having bannisters which increase the thickness of the stored apparatus; and the Graves device does not have means for properly supporting the stairway on uneven ground.
U.S. Pat. No. 3,796,456 issued to L. L. Bergeson, like Graves, utilizes parallel bars along the sides of the steps, thereby creating a potentially dangerous obstacle. The Bergeson apparatus retracts to a storage position below the vehicle and is therefore not useable on many vehicles. Bergeson also does not disclose any type of leveling means.
U.S. Pat. No. 3,392,990 issued to G. E. Wolf discloses a stairway which is slidable laterally to or from the doorway and may be pivoted upwardly for storage. The stairway of the Wolf device is not collapsible and is therefore bulky in the stored position. The Wolf device provides no platform nor does it provide means for leveling.
Other patents of interest but of lesser relevance are U.S. Pat Nos. 2,760,238; 3,515,406; 3,608,951; 3,708.198; and 4,188,057.